Investigations have been carried out for purification of oily wastewat
er by a combination of ultrafiltration/reverse osmosis processes. A tu
bular ultrafiltration system using cellulosic and non-cellulosic membr
anes was tested with typical oily wastewater collected from harbour an
d simulated emulsion without any pretreatment. Both membrane types pro
duced a permeate with an oil content generally less than 10 mg/dm(3).
Rejection of chemical oxygen demand (COD) is 80% for ultrafiltration t
reatment. The permeate is generally of acceptable quality for direct s
ewer discharge. For further treatment of UF permeate, reverse osmosis
was applied with tubular B1 PCI modules using cellulose acetate membra
nes. The rejection of COD after ultrafiltration/reverse osmosis treatm
ent increased up to 98.5% and total dissolved solids (TDS) to 95.7%. R
everse osmosis treatment will permit reuse of the treated water as pro
cess water.